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If a^2b^2c^3 = 4500. Is b+c = 7 ?

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If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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Updated on: 26 Aug 2018, 21:29
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Question Stats:

38% (01:32) correct 62% (01:23) wrong based on 383 sessions

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If $$a^2b^2c^3$$ = 4500. Is b+c = 7 ?

(1) a, b and c are positive integers
(2) a > b

Originally posted by GMATBaumgartner on 17 Oct 2012, 01:52.
Last edited by Bunuel on 26 Aug 2018, 21:29, edited 3 times in total.
Edited the question.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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17 Oct 2012, 03:56
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GMATBaumgartner wrote:
If a^2b^2c^3 = 4500. Is b+c = 7 ?

(1) a, b and c are positive integers
(2) a > b

what would be the most efficient way to approach this within 2 mins?

Given: $$a^2*b^2*c^3 = 4500=2^2*3^2*5^3$$. Question: is $$b+c=7$$

(1) a, b and c are positive integers --> sure it's possible that $$a=3$$, $$b=2$$ and $$c=5$$ and in this case the answer will be YES but it's also possible that $$a=2$$, $$b=3$$ and $$c=5$$ and in this case the answer will be NO. Not sufficient.

(2) a > b. Clearly insufficient.

(1)+(2) Note that we are not told that a, b and c are prime numbers, so again it's possible that $$a=3>2=b$$ and $$c=5$$ and in this case the answer will be YES but for example it's also possible that $$a=2^2*3^2=6^2$$, $$b=1$$ and $$c=5$$ ($$a^2*b^2*c^3 =6^2*1^2*5^3=4500$$) and in this case the answer will be NO. Not sufficient.

Hope it's clear.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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17 Oct 2012, 04:13
Thank you bunuel. I completely overlooked the part they there is NO mention of then as primes!

Is there any post where you sum up the important such 'overlook-ables' that we must crosscheck before marking a statement Sufficient or Not sufficient.

Thanks in advance.I am in the final leg of my prep,any advise would be much appreciated.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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17 Oct 2012, 05:03
Very often I overlook the possibilty of 0 in equalties. i.e. I check for only +ve and -ve numbers.

A list of the aforementioned "overlookables" would help a lot.
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Joined: 11 Apr 2012
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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17 Oct 2012, 19:49
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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23 Oct 2012, 06:40
1
4
GMATBaumgartner wrote:
Thank you bunuel. I completely overlooked the part they there is NO mention of then as primes!

Is there any post where you sum up the important such 'overlook-ables' that we must crosscheck before marking a statement Sufficient or Not sufficient.

Thanks in advance.I am in the final leg of my prep,any advise would be much appreciated.

data-sufficiency-strategy-guide-130264.html
trouble-with-quant-some-tips-traps-that-might-help-you-34329.html
tips-on-approaching-ds-questions-104945.html
http://gmatclub.com/blog/2010/01/verita ... questions/
http://gmatclub.com/blog/2010/09/elimin ... fficiency/
http://gmatclub.com/blog/2011/08/gmat-d ... tion-type/
http://gmatclub.com/blog/2011/08/must-k ... trategies/
http://gmatclub.com/blog/2011/08/kaplan ... questions/

Hope it helps.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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19 Jul 2013, 01:22
From 100 hardest questions.
Bumping for review and further discussion.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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Updated on: 19 Jul 2013, 12:49
Hi,

Sorry I think that answer is B. Here is my opinion: we are just able to re-write 4500=(3^2)*(2^2)*(5^3), right?

just we don't know that which one of 3 or 2 is a & b, correct?

statement 2 is giving us a>b then we know that a=3 and b=2 and problem solved.

I don't know where I went wrong? Can you explain my fault?

Edit: I found it!

Originally posted by zazoz on 19 Jul 2013, 12:41.
Last edited by zazoz on 19 Jul 2013, 12:49, edited 1 time in total.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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19 Jul 2013, 12:47
zazoz wrote:
Hi,

Sorry I think that answer is B. Here is my opinion: we are just able to re-write 4500=(3^2)*(2^2)*(5^3), right?

just we don't know that which one of 3 or 2 is a & b, correct?

statement 2 is giving us a>b then we know that a=3 and b=2 and problem solved.

I don't know where I went wrong? Can you explain my fault?

Pay attention to the examples given:

(1)+(2) Note that we are not told that a, b and c are prime numbers, so again it's possible that $$a=3>2=b$$ and $$c=5$$ and in this case the answer will be YES but for example it's also possible that $$a=2^2*3^2=6^2$$, $$b=1$$ and $$c=5$$ ($$a^2*b^2*c^3 =6^2*1^2*5^3=4500$$) and in this case the answer will be NO. Not sufficient.

Hope it's clear.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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19 Jul 2013, 12:49
Bunuel wrote:
zazoz wrote:
Hi,

Sorry I think that answer is B. Here is my opinion: we are just able to re-write 4500=(3^2)*(2^2)*(5^3), right?

just we don't know that which one of 3 or 2 is a & b, correct?

statement 2 is giving us a>b then we know that a=3 and b=2 and problem solved.

I don't know where I went wrong? Can you explain my fault?

Pay attention to the examples given:

(1)+(2) Note that we are not told that a, b and c are prime numbers, so again it's possible that $$a=3>2=b$$ and $$c=5$$ and in this case the answer will be YES but for example it's also possible that $$a=2^2*3^2=6^2$$, $$b=1$$ and $$c=5$$ ($$a^2*b^2*c^3 =6^2*1^2*5^3=4500$$) and in this case the answer will be NO. Not sufficient.

Hope it's clear.

yeah, I got it, thanks
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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16 Mar 2016, 21:56
If a^2b^2c^3 = 4500. Is b+c = 7 ?
(a^2) (b^2) (c^3) =4500=(30^2) 5
(abc)^2 c= (30^2) 5
If a, b and c are positive integers then we may have c=5 and abc=30 => ab=6

(1) a, b and c are positive integers
a, b and c are positive integers then we may have c=5 and abc=30 => ab=6.
but a=3,b=2 => b+c=7
a=6, b=1 => b+c=6 INSUFFICIENT
(2) a > b
a and b may be fractions and many combinations are posssible for a and b. INSUFFICIENT

combining 1 and 2
a=3,b=2 => b+c=7
a=6, b=1 => b+c=6 INSUFFICIENT

Hence E
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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25 Jul 2018, 11:00
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ? &nbs [#permalink] 25 Jul 2018, 11:00
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